If you do anything besides sign, I would simply point out that the letter is incorrect and why, and ask her to let you know when it's corrected.

I got served on 8/29/2013, and we didn't go for our first hearing until 10/7/2013, and even then they set our first trial date for 1/7/2014.

Now, my W is now telling me that she doesn't want divorce.

Getting served isn't necessarily the end of the world.